Recently there has been an increasing interest in the possibility of employing inductive energy storage in pulse power applications because of the high intrinsic capacity of such storage when compared with capacitive energy storage and also the fact that this energy can be transferred to the load in nanosecond time scales. The key to utilizing this technology is the availability of a repetitive fast opening switch. A leading contender for such an opening switch is the externally sustained diffuse gas discharge switch.
In a diffuse gas discharge switch, the diffuse discharge is substained by means of gas ionization either by an external electron beam, a laser beam or a combination of both. The fast opening of the switch is usually accomplished by adding an electronegative gas in the gas mixture which attaches the remaining electrons immediately after the external electron source is turned off. The switch opening time depends critically on the electron attachment properties of the electronegative gas. Laser induced enhancement of electron attachment could be used to minimize the switch opening time.
Enhanced electron attachment due to vibrationally excited ground electronic state molecules produced by laser irradiation has been investigated. However, this effect has an inherent disadvantage in the diffuse gas discharge switch in that these molecules can reach vibrational levels due to excitation caused by electron impact and thus lead to undesired electron attachment during the switch conduction phase. In contrast, electronically excited states have higher threshold energies and thus do not effect electron loss in the conduction phase. Therefore, there is a continuing need to provide gas mixtures for diffuse gas discharge switches that are capable of quickly removing free electrons from the switch when the switch is open but yet does not attach to electrons when the switch is closed.